Structural assembly for the prevention of thermal leakage



2 Shets-Shee July 25, 1967 J. R. BANGS STRUCTURAL ASSEMBLY FOR THE PREVENTION OF THERMAL LEAKAGE Filed July 25, 1964 INVENTOR:

JOHN R. BANGS ATTYSv fUI ooooooooo aoooooooooooo July 25, 1967 J. R. BANGS 3,332,170

STRUCTURAL ASSEMBLY FOR THE PREVENTION OF THERMAL LEAKAGE Filed July 23, 1964 2 Sheets-Sheet 2 F164 mz mg 65 E 64 f 97 m 8/ 92 A T 1 /W 1 INVENTORZ BY JOHN R. BANGS ATTYS.

United States Patent 3,332,170 STRUCTURAL ASSEMBLY FOR THE PREVENTION OF THERMAL LEAKAGE John R. Bangs, 611 Park St., E., Vienna, Va. 22180 Filed July 23, 1964, Ser. No. 384,714 Claims. (Cl. 4-4ll0) This invention relates to new and useful improvements in structural members and structural assemblies employing these structural members.

The present invention has particular application to and is extremely useful in the construction of refrigerated bodies for road and rail vehicles. The Walls defining these refrigerated bodies generally comprise a plurality of spaced beams or columns, for example I-beams and a thin, sheet-like material of metal secured in spaced apart relation to the opposed flanges of the beams defining the inner and outer skins of the wall and a body of insulating material such as urethane foam in the space between the skins. Even though this construction provides good insulation against heat transfer or leakage over a large area of the wall, nevertheless, there is heat transfer or leakage at those areas where the inner and outer skins are connected by the I-beams. At this juncture or connection there is a continuous thermal conduction path between the inner and outer skins through the beam and hence an area of thermal leakage.

The present invention solves this problem of thermal leakage in assemblies such as refrigerated bodies for road or rail vehicles by the provision of a composite beam member for use in the construction of walls of the refrigerated body assembly which broadly comprises two spaced apart metallic sections having interengaging spaced apart finger portions in the forms of spaced webs mounting fins thereon to define a labyrinthine space between the metallic sections which is filled with insulating material completely separating the webs and fins. By this arrangement there is provided a beam structure which has good compressive and fiectural strength so that it is capable of supporting a given load. Secondly, the structural arrangement of the beam is such that there is not a continuous conduction path between the metallic sections of the beam thereby drastically reducing thermal leakage.

Thus, when the beams are used in a wall assembly, the inner and outer skins are secured to the opposed metallic sections of the beams. Accordingly, in the wall assembly, there is no direct thermal conduction path between the inner and outer skins thereby eliminating thermal leakage without sacrificing the structural stability or strength of the entire assembly.

With the foregoing in mind, an object of the present invention is to provide a structural member including a pair of metallic sections having interleafing spaced portions and a body of insulating material separating the metallic sections thereby providing a structure having no direct thermal conduction path between the metal sections of the beam and good structural strength and rigidity.

A further object of the present invention is to provide a structural member or beam characterized by novel features of construction and arrangement which is easy and inexpensive to fabricate and assemble and which is extremely effective for the purposes intended.

A still further object of the present invention is to provide a structural assembly such as for a refrigerated body for a rail or road vehicle, characterized by good structural strength, is thermally leakproof, and is a comparatively lightweight structure for ease of assembly.

These and other objects of the present invention and the various features and details of a structural member in accordance with the present invention are hereinafter 3,332,170 Patented July 25, 1967 more fully set forth with reference to the accompanying drawings, wherein:

FIG. 1 is a perspective view of a composite structural member in the form of an I-beam in accordance with the present invention;

FIG. 2 is a fragmentary plan view partly in section of a wall assembly incorporating structural members of the type illustrated in FIG. 1;

FIG. 3 is an enlarged sectional view taken on lines 33 of FIG. 2; and

FIG. 4 is an enlarged fragmentary sectional view of an assembly incorporating another form of composite structural member in accordance with the present invention.

In accordance with the present invention, the structural member comprises two elongated confronting, spaced apart plate members preferably made of a metal such as an aluminum alloy having interleafing spaced finger portions of a configuration to define a labyrinthian space between the metallic sections which is filled with a body of insulating material such as urethane foam. By this arrangement there is provided a structural member which has strength and rigidity and which moveover is characterized by a non-heat conducting path between the plate members. Thus, when the structural member is used, for example, as the supporting frame for a wall of a refrigerated body of a rail or road vehicle, the inner and outer skins of the wall are supported in spaced relation on opposite ones of the plate members and the space between the skins filled with insulating material. Accordingly, there is a true insulation between the inner and outer skins throughout the entire assembly.

Referring now to the drawings, there is shown in FIG. 1 a structural member 10 in accordance with the present invention. The structural member 10 is in the form of an I-beam; however, it is to be understood that the principle of the invention applies to other forms of structural members. The structural member 10 illustrated in FIG. 1 comprises a pair of elongated generally rectangular, flat, plate members 12 and 14 respectively arranged in confronting parallel relation. The plate member 12 has in the present instance a pair of spaced webs 16 and 18 projecting from the inner face thereof which is illustrated, are coextentensive with the member 12 and spaced inwardly from the side edges thereof to define outer side flange portions 12a and 12b with openings 13 therein to receive rivets or the like for securing walls to the plate members. The plate member 14 has a single web 20 which projects from the inner face of and is coextensive with the plate member 14. The web 20 is spaced approximately centrally of the side edges of the plate member 14 so that in the assembled structural member it is disposed between the webs 16 and 18. The plate member 14 also has flange portions 14a and 14b adjacent outer side edges thereof having openings 15 therein for receiving fasteners such as rivets to secure walls thereto.

The structural member includes a plurality of fins projecting from the side faces of the webs which are spaced apart and oriented in a manner to define in cross section a labyrinthine or maze-like configuration. More specifically, in the illustrated embodiment of structural member shown in FIG. 1 the web 16 has a pair of fins 16f projecting from the inner face thereof, one fin at the free end of the Web 16 and the other fin disposed approximately midway between the free edge of the web 16 and the inner face of the plate member 12. The web 18 also has a pair of fins 18f which projects from the inner face of the web 18 and is parallel to the fins 16 The web 20 as illustrated projects from the inner face of the plate member 14 between the webs 16 and 18 and has pairs of fins 20f projecting from opposite faces of the web 20 which are staggered relative to the fins 16f and 18] to define a labyrinthine 3 cavity C which is filled with a body 27 of insulating material such as a polyurethane foam.

It has been found that optimum load bearing capacity and thermal properties of the structural member are realized when the various elements thereof have a predetermined relation to one another. For example, it has been found that it is desirable to use a body of insulating material in the nature of a semi-flexible foam of approximately 6080 durometer hardness which provides the desired thermal characteristics and is also able to withstand impact stresses in shear or compression. Further, the strength and thermal characteristics of the structural member are best balanced by making the outer webs 16 and 18 and fins 16,, 18 and 20) of a predetermined cross section or thickness, that is, approximately half the cross section or thickness of the central web and in turn making the central web of smaller thickness or cross section than the opposing plate members. In this regard it is noted that optimum strength and thermal characteristics are achieved by making the fins overlap one another at their tip ends for approximately 20 percent of the length thereof. For example, for a given structural member of a size 4" x 4", wherein the metallic sections are made of an aluminum alloy, for example the opposing plate members 12 and 14 may be made of a cross section 0.125 inch, the outer webs 16 and 18 and fins may be made of a cross section of 0.030 inch and the central web 20 may be made of a thickness 0.060 inch. By this arrangement, the composite beam has comparable strength characteristics to a conventional 4" x 4" I-beam, the plate members and connecting piece of which are of much greater cross section and much heavier. In addition the composite beam or structural member of the present invention as noted previously, has excellent thermal characteristics; that is, by this specific structure there is no continuous thermal path between the opposing plate members.

In making a structural member, in accordance with the present invention, the metallic sections are supported in the desired spaced apart relation by suitable fixtures or the like. The open ends between the terminal ends of the webs 16 and 18 and the inner face of the plate member 14 and the top and bottom ends are suitably sealed off. Thereafter, a body of insulating material, for example, polyurethane foam is introduced through openings 41 in one of the plate members. After a suitable curing period has elapsed, the structural member may be removed from the fixtures and is ready for use.

The structural members of the present invention may be used as the vertical posts and horizontal joist or girders of a refrigerated body for a road or rail vehicle. A wall 51 of such an assembly is illustrated in FIGS. 2 and 3. As illustrated therein, the wall 51 comprises inner and outer skin members 40 and 42 made for example, of metal such as aluminum or steel or plywood or plastic. The inner and outer skins are supported in spaced apart relation by the structural members constructed in accordance with the present invention by means of rivets engaging through the skin and openings in the flange portions. A body of insulating material 44 is provided in between the inner and outer skins 40 and 42. This body of insulating material 44 may be preformed in sheets and inserted between the structural members prior to assembly of the skins. Alternatively, the inner and outer skins may be assembled to the structural members 10 and thereafter in the case of a foam material such as polyurethane, the foam may be poured into the space between the skins to form the body 44.

There is illustrated in FIG. 4 a fragmentary portion of a structural assembly embodying another form of structural member in accordance with the present invention. In the assembly illustrated, the structural member 60 is a beam at the end of the sidewall 62 of a truck body or the like and the structural member 64 is a post for a door 66 closing the open end of the truck, door 66 being, connected to the post 64 by a series of conventional hinges 68. The

structural member comprises a pair of spaced inner and outer plate members 70 and 72 respectively. The inner plate member has an angularly offset portion 73 and a pair of webs 74a and 74b, one of the webs 74a projecting from the inner face thereof spaced inwardly from the outer side edge of the plate members 70 to define a flange portion 75, the other web 741; projecting from the free end of the offset portion 73. The plate member 72 has a web 76 projecting from one face thereof disposed between the webs 74a and 74b of the inner plate member 70. Each of the webs has fins projecting therefrom arrayed in staggered relation in the manner illustrated in FIG. 4 to define a labyrinthine cavity therebetween adapted to be filled with a body 77 of insulating material such as a urethane foam. In the present instance the outer plate member 72 has an extension 79 terminating in a generally S- shaped terminal end portion 81 to provide a stepped configuration at one end of the structural member.

The structural member 64 is designed to cooperate with the structural member 60 to provide a sealed and thermally insulated closure when the door is closed. To this end, the structural member 64 comprises inner and outer plate members and 92 respectively, the inner plate member having an offset inner portion 93 which is substantially parallel to the offset portion 73 when the structural members are in the positions shown in FIG. 4. The inner plate member 90 has a pair of Webs 94a, 94b, one of the webs 94a projecting from the inner face at a point spaced inwardly from the inner edge of the plate member 90 to define a flange portion 95 for securing one wall of the door assembly thereto. The other web 94b projects from the offset portion 93. The outer plate member 92 has a web 96 disposed between the webs 94. The webs mount a plurality of fins 97 which are staggered as illustrated to define a labyrinthine cavity for a body of insulating material. In the present instance, the outer plate member 92 is extended and has an backward C-shaped section 101 at its terminal end which conforms to the end portion 81 of the structural member 60. In the present instance, soft rubber gaskets 103 are provided which may be adhered in the present instance to the structural member 60 at the stepped junctures of the structural members 60 and 64. In the present in stance the wall of the outer plate members 72 and 92 is of greater cross section as at and 102 respectively to facilitate atttachment of the hinge thereto and provide a stronger structural assembly for supporting the weight of the door.

As in the first described embodiment, the strength and thermal characteristics of the structural members illustrated in FIG. 3 are best balanced by making the plate members, webs and fins in predetermined cross section or thickness relative to one another. Thus, the webs 74a, 94a, 76 and 96 are preferably of a cross section or thickness less than the thickness or cross section of the plate members. Further, the outer webs 74b and 94b and the fins are of approximately the same cross section and approximately one-half the cross section or thickness of the webs 74a, 94a, 76 and 96. As in the previously described embodiment, the fins preferably overlap one another at their tip ends for approximately 20 percent of the length thereof.

These structural members may be made in much the same way as the structural members described in the previous embodiment. Thus, the inner and outer plate members of each structural assembly are supported in predetermined relation with respect to one another and thereafter the insulating material in the form for example of a urethane foam may be deposited in the labyrinthine cavity between the members. After the foam has set, the structural members may be assembled to form the end posts for the wall 62 of a refrigerated body and the structural member 64 may be assembled to the panel comprising a door.

While particular embodiments of the present invention have been illustrated and described herein, it is to be understood that it is not to limit the invention to such disclosure and that changes and modifications may be made therein within the scope of the following claims.

I claim: v

1. A pair of structural members, one of which provides a beam for a wall assembly and the other of which provides a post for a door attached to said wall assembly, said other structural members comprising a pair of spaced inner and outer plate members, said inner and outer plate members having interleafing finger portions defining a labyrinthine space and a body of insulating material filling said labyrinthine space, said inner plate member having an offset portion and said outer plate member having an extension terminating in a backward C-shaped terminal portion to provide a stepped configuration at one end of said structural member, said one structural member comprising a pair of confronting spaced inner and outer plate members, said plate members having interleafing spaced finger portions defining a labyrinthine space therebetween filled with a body of insulating material, said inner plate member of said one structural member having an offset portion substantially parallel to the offset portion of said other structural member and said outer plate member of said one structural member terminat-ing in a generally S-shaped section at its terminal end to provide a stepped configuration at one end of said structural member conforming to the stepped configuration of said first structural member.

2. A structural assembly as claimed in claim 1 including sealing means between the confronting stepped ends of said structural members.

3. A structural member comprising a pair of confronting elongated plate members having confronting spaced apart inner faces, one of said plate members having at least a pair of spaced first webs projecting from its inner face, the other of said plate members having at least one second web member projecting from its inner face disposed between said pair of web members of said one plate, said first webs having a plurality of aligned fins projecting from the confronting sides of said first webs, said second web having fins projecting from opposite sides staggered relative to the fins of said first webs to define a labyrinthine space between the plate members and a body of insulating material filling said labyrinthine space, said first webs and fins being approximately onehalf the thickness of said second web and said second web being of a smaller cross section than said plate members.

4. A structural member comprising a pair of confronting elongated plate members having confronting spaced apart inner faces, one of said plate members having at least a pair of spaced first webs projecting from its inner face, the other of said plate members having at least one second web member projecting from its inner face disposed between said pair of web members of said one plate, said first webs having a plurality of aligned fins projecting from the confronting sides of said first webs, said second web having fins projecting from opposite sides staggered relative to the fins of said first webs to define a labyrinthine space between the plate members and a body of insulating material filling said labyrinthine space the fins of said first and second webs overlapping oneanother by approximately 20% of their length.

5. A structural member as claimed in claim 4 wherein said insulating material is a urethane foam.

References Cited UNITED STATES PATENTS 2,869,336 1/1959 Smidl et al. 52-309 X 2,882,701 4/1959 Nelson et al. 52404X 3,003,810 10/1961 Kloote et a1. 52288 X 3,014,611 12/ 1961 Marshall 52404 X 3,099,337 7/1963 Hetman 52400 FRANK L. ABBOTT, Primary Examiner.

M. O. WARNECKE, Assistant Examiner. 

1. A PAIR OF STRUCTURAL MEMBERS, ONE OF WHICH PROVIDES A BEAM FOR A WALL ASSEMBLY AND THE OTHER OF WHICH PROVIDES A POST FOR A DOOR ATTACHED TO SAID WALL ASSEMBLY, SAID OTHER STRUCTURAL MEMBERS COMPRISING A PAIR OF SPACED INNER AND OUTER PLATE MEMBERS, SAID INNER AND OUTER PLATE MEMBERS HAVING INTERLEAFING FINGER PORTIONS DEFINING A LABYRINTHINE SPACE AND A BODY OF INSULATING MATERIAL FILLING SAID LABYRINTHINE SPACE, SAID INNER PLATE MEMBER HAVING AN OFFSET PORTION AND SAID OUTER PLATE MEMBER HAVING AN EXTENSION TERMINATING IN A BACKWARD C-SHAPED TERMINAL PORTION TO PROVIDE A STEPPED CONFIGURATION AT ONE END OF SAID STRUCTURAL MEMBER, SAID ONE STRUCTURAL MEMBER COMPRISING A PAIR OF CONFRONTING SPACED INNER AND OUTER PLATE MEMBERS, SAID PLATE MEMBERS HAVING INTERLEAFING SPACED FINGERS PORTIONS DEFINING A LABYRINTHINE SPACE THEREBETWEEN FILLED WITH A BODY OF INSULATING MATERIAL, SAID INNER PLATE MEMBER OF SAID ONE STRUCTURAL MEMBER HAVING AN OFFSET PORTION SUBSTANTIALLY PARALLEL TO THE OFFSET PORTION OF SAID OTHER STRUCTURAL MEMBER AND SAID OUTER PLATE MEMBER OF SAID ONE STRUCTURAL MEMBER TERMINATING IN A GENERALLY S-SHAPED SECTION AT ITS TERMINAL END TO PROVIDE A STEPPED CONFIGURATION AT ONE END OF SAID STRUCTURAL MEMBER CONFORMING TO THE STEPPED CONFIGURATION OF SAID FIRST STRUCTURAL MEMBER. 